After two boys find a human skeleton in the the Don Valley woods, Detective Murdoch finds himself investigating the nearby residents of a naturist colony run by Helmut Lindemann and his wife Irene. From what they've been able to retrieve Dr. Grace determines that the skeleton is that of a male, approximately 40 years old, who was shot through the heart. Murdoch wants to find the bullet and uses his induction balancing machine - a metal detector - for the task. When they find a prosthetic arm near the river, Dr. Grace is reasonably certain it belonged to the victim. Dr, Rico, a prosthetics maker identifies it as belonging to an American gentleman, Zacharia Marsh. They learn that Marsh was a famous Pinkerton man who years ago took down the infamous Rooster gang. They decide to send Crabtree under cover, so to speak, at the nudist colony to see what he can learn. At the station meanwhile, Inspector Brackenreid is doing all he can to avoid Jean Hamilton, the protector of Toronto's morals, who wants the police to do something about a Paris revue that is coming to the city.